Chemical composition, determination, and prediction of energy values of different sugarcane yeasts for broiler...

The growing demand for sustainable and cost-effective feed ingredients in poultry production has highlighted agro-industrial by-products like sugarcane yeast, which can address environmental waste from the sugar and alcohol industry while providing nutritional benefits for broiler chickens. This study aimed to determine the energy values of 4 yeast samples and develop prediction equations based on their chemical composition, hypothesizing that variations would influence metabolizable energy across broiler growth stages. Samples were analyzed for physicochemical properties (e.g., crude protein, CP: 14.94-21.12%; gross energy: 4011-4268 kcal kg^-1), and digestibility tests were conducted on 690 male Cobb 500 broilers in a completely randomized design across 4 phases (1-8 days, 11-18 days, 21-28 days, and 31-38 days), using reference and yeast-enriched diets (30% inclusion), followed by multiple regression analysis. Apparent metabolizable energy (AME) and corrected AME (AME_n) values ranged from 800 to 2223 kcal kg^-1 and 698-2069 kcal kg^-1, respectively, with the best equation being AME = 8905.51 - 32.1006 × age - 81.048 × DM + 0.50052 × MGD (R² = 0.6798), where DM is dry matter. Yeast's energy values are influenced by origin and composition, enabling accurate predictions for broiler chickens. Implications: These findings support the use of sugarcane yeast in poultry feeds, enhancing sustainability, reducing industry waste, and improving feed efficiency for global livestock and food production.